I find the study's conclusion that "leisure digital reading does not seem to pay off in terms of reading comprehension, at least as much as traditional print reading does," unsubstantiated by their findings. The authors acknowledge in the Limitations section that there is significant heterogeneity across effect sizes, preventing them from drawing conclusions across age groups. Therefore, it is questionable to assert an effect across the lifespan. Notably, the majority of participants in their analyzed sample were middle school (35.89%) and high school (35.89%) students.

Note that the authors define leisure digital reading habits as those typically observed in this age group, encompassing activities such as time spent on digital texts for social communication (e.g., instant messaging, online chatting, emailing, checking social media) or informative-linear reading (e.g., searching for information on the Internet, browsing websites, blogs, or forums, reading e-books, e-magazines, or e-comics). It is crucial to differentiate this type of digital reading from interactive digital books designed for young children, which guide them through images, texts with embedded questions, or reading supports to enhance comprehension.

In sum: The study's conclusion that "leisure digital reading does not seem to benefit reading comprehension as much as traditional print reading across lifespan" lacks adequate support, given the acknowledged heterogeneity in effect sizes. The majority of participants in the analysed sample were middle and high school students. Additionally, the authors do not differentiate leisure digital reading habits (associated with activities like social communication and informative-linear reading), from interactive digital books designed for young children that provide reading comprehension support.